Fuel supply device for internal combustion engine

Abstract

A fuel supply device for an internal combustion engine having an intake manifold includes a throttle body defining therein an intake passage communicating at one end thereof with the intake manifold. A flow accelerating valve arranged in the intake passage upstream of a throttle valve cooperates with the wall surface of the intake passage to define a flow accelerating passage of a smaller flow area than the intake passage. The flow accelerating valve is angularly movable in response to a change in the intake fluid flow between a fully closed position in which the flow accelerating passage has a minimum flow area and a fully open position in which the flow accelerating passage has a maximum flow area, to thereby control the flow area of the flow accelerating passage. A fuel injector injects liquid fuel into the accelerated intake fluid flow passing through the flow accelerating passage.

What we claim is: 
     
       1. A fuel supply device for an internal combustion engine including an intake manifold, the fuel supply device comprising: a throttle body defining therein an intake passage having one end thereof communicating with said intake manifold;   a throttle valve in said intake passage for controlling intake fluid flow introduced into the engine through said intake passage and said intake manifold;   flow accelerating means disposed in said intake passage upstream of said throttle valve, said flow accelerating means cooperating with the wall surface of said intake passage to define therein an accelerating flow passage having a flow area less than that of said intake passage, the intake fluid flow passing through said intake passage being accelerated when the intake fluid flow passes through said accelerating flow passage, said flow accelerating means being movable in response to a change in the intake fluid flow introduced into the engine through said intake passage between a fully closed position in which said accelerating flow passage has a minimum flow area and a fully open position in which said accelerating flow passage has a maximum flow area, to control the flow area of said accelerating flow passage; and   a fuel injector having a nozzle disposed upstream of said throttle valve and downstream of said flow accelerating means when the flow accelerating means is in the fully closed position, said fuel injector being adapted to inject liquid fuel through said nozzle into the accelerated intake fluid flow passing through said accelerating flow passage and being disposed so as to be directed toward said accelerating flow passage such that the fuel injected from said injector does not substantially impinge against said flow accelerating means over the entire operating range of the engine.   
     
     
       2. A fuel supply device defined in claim 1, further comprising a wall member disposed in said accelerating flow passage to divide the same into a first flow passage section having a fixed flow area and a second flow passage section having a variable flow area. 
     
     
       3. A fuel supply device for an internal combustion engine including an intake manifold, the fuel supply device comprising: a throttle body defining therein an intake passage having one end thereof communicating with said intake manifold;   a throttle valve in said intake passage for controlling intake fluid flow introduced into the engine through said intake passage and said intake manifold;   flow accelerating means disposed in said intake passage upstream of said throttle valve, said flow accelerating means cooperating with the wall surface of said intake passage to define therein an accelerating flow passage having a flow area less than that of said intake passage, the intake fluid flow passing through said intake passage being accelerated when the intake fluid flow passes through said accelerating flow passage, said flow accelerating means being movable in response to a change in the intake fluid flow introduced into the engine through said intake passage between a fully closed position in which said accelerating flow passage has a minimum flow area and a fully opened position in which said accelerating flow passage has a maximum flow area, to control the flow area of said accelerating flow passage;   the fuel injector having a nozzle disposed upstream of said throttle valve and downstream of said flow accelerating means when the flow accelerating means is in the fully closed position, said fuel injector injecting liquid fuel through said nozzle into the accelerated intake fluid flow passing through said accelerating flow passage; and   a wall member disposed in said accelerating flow passage to divide the same into a first flow passage section having a fixed flow area and a second flow passage section having a variable flow area, said first flow passage section has a generally cylindrical downstream end portion, said nozzle of said fuel injector is disposed in said downstream end portion with an annular space left between said nozzle and a wall surface of said downstream end portion.   
     
     
       4. A fuel supply device defined in claim 3, wherein said nozzle of said fuel injector is disposed in substantially concentric relation to said downstream end portion of said first flow passage section. 
     
     
       5. A fuel supply device defined in claim 1, wherein said flow accelerating means includes a flat plate having an indentation cooperating with the wall surface of said intake passage to define said accelerating flow passage, and a shaft secured to said flat plate and rotatably supported by said throttle body, said shaft having an axis of rotation extending through said flat plate so as to divide said flat plate into two plate sections, one of said two plate sections having a surface area greater than a surface area of the other plate section, said indentation being provided in said one plate section. 
     
     
       6. A fuel supply device defined in any one of claims 2-4, wherein said flow accelerating means includes a flat plate having an indentation cooperating with the wall surface of said intake passage to define said accelerating flow passage, and a shaft secured to said flat plate and rotatably supported by said throttle body, said shaft having an axis of rotation extending through said flat plate so as to divide said flat plate into two plate sections, one of said two plate sections having a surface area greater than a surface area of the other plate section, said indentation being provided in said one plate section. 
     
     
       7. A fuel supply device defined in claim 6, wherein said indentation in said flat plate cooperates with said wall member to define said second flow passage section of said flow accelerating passage. 
     
     
       8. A fuel supply device defined in any one of claims 1-5, further comprising means for normally biasing said flow accelerating means into the fully closed position, said flow accelerating means being movable against said biasing means in response to an increase in the intake fluid flow introduced into the engine through said intake manifold from said fully closed position toward said fully opened position. 
     
     
       9. A fuel supply device defined in any one of claims 1-5, wherein said nozzle of said fuel injector is directed against said throttle valve. 
     
     
       10. A fuel supply device defined in claim 9, wherein said throttle valve includes a flat plate and a shaft secured thereto and rotatably supported by said throttle body, said shaft of said throttle valve having an axis of rotation extending through said throttle valve so as to divide said flat plate of said throttle valve into two plate sections, said nozzle of said fuel injector being directed to one of said two plate sections of said throttle valve that is remote from said nozzle. 
     
     
       11. A fuel supply device defined in any one of claims 1-5, wherein said fuel injector injects liquid fuel through said nozzle at an injection pressure of approximately 0.7-1.0 Kg/cm 2 . 
     
     
       12. A fuel supply device defined in claim 10, wherein said fuel injector injects liquid fuel through said nozzle at an injection pressure of approximately 0.7-1.0 Kg/cm 2 .